Warbringer FarmingThere are five Zandalari Warbringer spawn points located throughout Pandaria, and the mobs themselves tend to respawn anywhere between 30 and 50 minutes after they've been killed. Many classes can handle the warbringers with relative ease, and nearly any damage-dealing class in Normal+ SoO gear should be able to solo them. They drop rep tokens (which can be useful for alts), two kinds of bags with supplies to use or sell, and in rare instances, one of three mounts: Jade, Amber, and Slate Primordial Direhorns.
If I'm in a group I'll generally head to the spawn point in Kun Lai while my partner heads to Jade Forest, with them looping back if the mob is up in Kun Lai. Then, hearth to the Shrine and strike out again, one to Townlong and one to Dread Wastes. Finish up in Krasarang and repeat the loop, if you are so inclined. If you pay attention to spawn times and there's not much competition out there, it's possible to travel from kill to kill to kill with little time spent waiting for respawns.
Riches of Pandaria & Glorious!Both of these achievements have you seeking out things. Tucked-away artifacts to find for the former, NPCs to kill for the latter. If you're max level you shouldn't encounter too many issues with the mobs for Glorious. Riches simply takes a bit of time; the nice thing is you'll get a hefty chunk of gold throughout the course of completing these, plus the chance at rare and vanity items from some of the mobs.
Given that we're at the tail end of this expansion, competition for mobs and treasures should be at an all-time low. Some addons you might want to check out to make this even easier: NPCScan, Finders & Riches, TomTom.